Natural weather ageing of starch/polyvinyl alcohol blend: effect of glycerol content

2013 ◽  
Vol 33 (3) ◽  
pp. 257-263 ◽  
Author(s):  
Sreekumar Parambathmadhom Appu ◽  
Sadhan Kumar De ◽  
Massihullah J. Khan ◽  
Mamdouh A. Al-Harthi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrogen Bonding ◽  
Polyvinyl Alcohol ◽  
Weather Conditions ◽  
Intermolecular Hydrogen Bonding ◽  
Biodegradable Material ◽  
Glycerol Content ◽  
Fourier Transfer Infrared Spectroscopy ◽  
Scanning Electron

Abstract Starch plasticized with glycerol and blended with polyvinyl alcohol (PVA) is recommended for use as a biodegradable material. The present article reports the results of studies of the natural weather ageing of starch/PVA blends having various amounts of glycerol in natural weather conditions of Saudi Arabia, with special reference to morphology and thermal behavior. Neat PVA has been used as a control to understand its behavior in its blend with starch. Differential scanning calorimeter studies indicated that an increase in the exposure time of samples to natural environment increases the crystallinity of PVA due to the breakage of intermolecular hydrogen bonding, thus facilitating the removal of the amorphous portion of the polymers in the blend. Thermogravimetric analysis revealed that an increase in glycerol content enhanced the degradation of the polymer, which is corroborated with the findings from the surface morphology using scanning electron microscopy and Fourier transfer infrared spectroscopy analyses.

Immobilized Bio-Beads with Activated Carbon Fiber for Removal of Benzene

2010 ◽  
Vol 96 ◽  
pp. 93-98 ◽  
Author(s):  
Xiu Li Liu ◽  
Lin Zhao ◽  
She Jiang Liu ◽  
Lu Hua You
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Activated Carbon ◽  
Carbon Fiber ◽  
Polyvinyl Alcohol ◽  
Calcium Alginate ◽  
Activated Carbon Fiber ◽  
Carrier Material ◽  
Removal Process ◽  
Scanning Electron

Two kinds of new immobilized bio-beads in gel were produced with calcium alginate, polyvinyl alcohol and activated carbon fiber. Scanning electron microscopy was used to detect the microstructure and MB were applied to enhance degradation of benzene. It shows that activated carbon fiber was a excellent carrier material to increase MB stability and enhance the degradation of benzene by changing the microsructure. CA-MB in this study was characteristic of loose interface, intensely homogeneous holes and well-reusability. 80% of benzene could be reduced after120h and removal tallied with one-order knetics.Otherwise,for PVA-MB, it possed more compact ouside and irregular tunnles and poles inside.Benzene removal process was analysed to compose of absorption and biodegradation.The immobilization inoculum of 137.77mg/L was optimal with the most stabilities and the best degradation capability for both CA-MB and PVA-MB. Moreover, it is the addition of ACF as encapsulated carrier that made CA-MB superior to PVA-MB in benzene removal and reutilization.

scholarly journals Copper corrosion inhibitors based on polyvinyl alcohol and silver nanoparticles

2019 ◽  
Vol 25 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Roxana Grecu ◽  
Adriana Samide ◽  
Gabriela Iacobescu ◽  
Nicoleta Cioateră ◽  
Alexandru Popescu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Hydrochloric Acid ◽  
Polyvinyl Alcohol ◽  
Acid Solution ◽  
Corrosion Inhibitors ◽  
Copper Surface ◽  
Copper Corrosion ◽  
Scanning Electron

Polyvinyl alcohol (PVA) and silver nanoparticles/poly(vinyl) alcohol system (nAg/PVA) were investigated as copper corrosion inhibitors in hydrochloric acid solution by electrochemical measurements, such as potentiodynamic polarization and cyclic voltammetry associated with the atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) analysis. The potentiodynamic curves processed as a semilogarithmic diagram were employed for corrosion current density (icorr) computing that reached the highest value for copper corrosion in uninhibited hydrochloric acid solution and the lowest value in nAg/PVA inhibitor presence, resulting in a picked-up inhibition performance, greater than 95%. Recording ten cycles of CV, the initiation, development and stability of upper-layer formed on the copper surface in the presence of inhibitors was confirmed. It can be asserted that PVA acts by the adsorption of Cu(II)-PVA complexes or crosslinked PVA-copper aggregates and additionally, in the presence of nAg/PVA of some compounds involving silver attached to PVA. AFM 3D images showed completely different morphologies of the copper surface layers formed in the absence and presence of inhibitors. Just like AFM, a more regular and uniform arrangement of the surface layer, due to the silver interconnected to PVA macromolecular chain, was displayed by scanning electron microscopy (SEM) images.

scholarly journals ТЕХНОЛОГІЯ ОДЕРЖАННЯ УЛЬТРАТОНКИХ НЕТКАНИХ МАТЕРІАЛІВ НА ОСНОВІ ПОЛІМЕРНИХ КОМПОЗИЦІЙ З ХІТОЗАНОМ

2021 ◽  
Vol 148 (4) ◽  
pp. 107-116
Author(s):  
О. В. Іщенко ◽  
В. П. Плаван ◽  
І. О. Ляшок ◽  
Т. В. Шевчук ◽  
З. С. Патрихіна
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Surface Tension ◽  
Polyvinyl Alcohol ◽  
Polyvinyl Acetate ◽  
Polymer Composition ◽  
Nonwoven Materials ◽  
Scanning Electron ◽  
Acetic Acids

The  aim  of  the  scientific  work  is  to  develop  a  technology  for  obtaining  of  ultrafine nonwoven  materials  based  on  a  polymer  composition  of  polyvinyl  alcohol  and  polyvinyl  acetate  with  the addition of chitosan, which was dissolved in lactic and acetic acids. Methodology. To assess the characteristics of the compositions, the viscosity and surface tension of working solutions were determined by capillary viscometry, and electrical conductivity - by conductometric method.  The  effect  of  thermal  stabilization  of  materials  based  on  chitosan  was  investigated  using  their sorption  properties.  The  morphological  composition  of  nonwovens  was  investigated  by  the  method  of scanning electron microscopy. Findings.  A  technology  has  been  developed  for  the  obtaining  of  ultrafine  materials  based  on chitosan dissolved in lactic and acetic acids by the method of electrospinning. The parameters for obtaining fibers from the studied compositions were determined. As a result of the analysis of the obtained ultrafine nonwoven  materials  by  the  method  of  scanning  electron  microscopy,  it  was  found  that  with  a  voltage between  the  electrodes  of  30  kV,  fibers  with  a  diameter  of  0.3  to  0.9  μm  are obtained.  According  to the statistical distribution of the diameters of polymer fibers in ultrafine nonwoven materials, it was determined that, depending on the components of the composition, 72-77% of the fibers have a diameter of 0.3 μm. Originality.  The  scientific  novelty  of  the  work  lies  in  the  determination  of  the  basic  laws  of  the electrospinning process using the natural polymer of chitosan and the peculiarities of the preparation of its solutions  in  lactic  and  acetic  acids.  The  effect  of  viscosity,  surface  tension  and  electrical  conductivity  of working solutions of the compositions on the process of electrospinning has been established. Practical value. Technological parameters for the obtaining of ultrafine nonwoven materials based on  the  composition  of  polyvinyl  alcohol  and  polyvinyl  acetate  with  the  addition  of  chitosan  have  been developed by the method of electrospinning; the possibility of adjusting the fiber diameter by choosing a chitosan solvent has been determined.

Mass-Producible Organic Nanocapsule with Water-Responsive Releasing Ability

2018 ◽  
Vol 916 ◽  
pp. 14-18
Author(s):  
Masaki Kogiso ◽  
Wu Xiao Ding ◽  
Mitsutoshi Masuda
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrogen Bonding ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Zinc Acetate ◽  
Organic Dyes ◽  
Lipid Complex ◽  
Hydrogen Bonding Networks ◽  
Scanning Electron

An organic nanocapsule was obtained by mixing zinc acetate powder into a peptide lipid dispersion in ethanol. The nanocapsule was mass-produced at a scale of over 100 g L–1 within 1 h. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that a zinc-peptide lipid complex was formed within 15 min, which subsequently transformed into a nanocapsule as a result of changes in the hydrogen bonding networks between the peptides. A variety of organic dyes could be encapsulated by simply adding them during the nanocapsule formation. We also confirmed their high stabilities in organic solvents, water-responsive morphological change, and resulting guest release. The water-responsive nanocapsule is expected to be useful in a variety of fields.

scholarly journals Scanning electron microscopy in the tests of fibre-cement boards

2018 ◽  
Vol 174 ◽  
pp. 02015
Author(s):  
Anna Adamczak-Bugno ◽  
Grzegorz Świt ◽  
Aleksandra Krampikowska
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Environmental Factors ◽  
Weather Conditions ◽  
Microscopic Method ◽  
Is Research ◽  
The Subject ◽  
Fibre Cement ◽  
Scanning Electron

The subject of this article is research on fiber-cement boards, which are currently used in civil engineering as cladding for ventilated facades, but also as internal claddings. When these boards are used on elevations, they are exposed to changing weather conditions, and therefore they are given the appropriate requirements for strength, mass moisture, absorbability and, above all, durability in accordance with the relevant regulations. The paper presents a proposal for using a nondestructive microscopic method for testing fiber-cement boards using a scanning electron microscope (SEM) with an EDS analyzer. Fibercement boards subjected to various environmental factors (moisturizing, freezing-thawing) and exceptional factors (burning at 230°C and setting on fire for 5 and 10 minutes) were tested. Interesting research results were obtained, which allowed to observe changes occurring in the microstructure of the tested boards under the influence of various factors.

scholarly journals Tenebrio molitor and its gut bacteria growth in polystyrene (PS) presence as the sole source carbon

2020 ◽  
Vol 25 (1) ◽  
pp. 37-53
Author(s):  
Paula M Peña-Pascagaza ◽  
Nathalia A López-Ramírez ◽  
Miguel A Ballen-Segura
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Carbon Source ◽  
Digestive Tract ◽  
Tenebrio Molitor ◽  
Sole Source ◽  
Biodegradable Material ◽  
Bacteria Growth ◽  
Natural Microbiota ◽  
Scanning Electron

Although polystyrene (PS) is considered a non-biodegradable material, recent work has shown the degradation capacity of this material by microorganisms, especially those that are part of the natural microbiota of the digestive tract of some invertebrates. The present work sought to evaluate the growth of the larva of the mealworm (Tenebrio molitor) and its bacteria, using PS as the sole source of carbon. In this way it was possible to demonstrate the consumption of PS plates by the larva, found in holes and tunnels in the material, however, nutritionally it is not enough for the larva to gain biomass, notably reducing its size and time survival. Similarly, bacteria isolated from the digestive tract of T. molitor presented the ability to generate biofilms o n PS s heets, g enerating c hanges ( cracks, holes, etc.) in them, which were observed under scanning electron microscopy (SEM), indicating the possible use of this material as a carbon source for its growth.

scholarly journals Effect on honey concentration on morphology of bubble-electrospun polyvinyl alcohol/honey fibers

2016 ◽  
Vol 20 (3) ◽  
pp. 1012-1013 ◽  
Author(s):  
Chang Liu ◽  
Lan Xu ◽  
Fujuan Liu ◽  
Ji-Huan He
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
Mean Diameter ◽  
The Mean ◽  
Surface Morphologies ◽  
Scanning Electron

In this study, polyvinyl alcohol fibers containing honey were produced by bubble electrospinning. The surface morphologies of polyvinyl alcohol fibers were studied by a scanning electron microscopy. The results showed the mean diameter of fibers increased as the ratio of honey increased.

scholarly journals Research on morphologies of polyvinyl alcohol/milk nanofibers

2016 ◽  
Vol 20 (3) ◽  
pp. 961-966
Author(s):  
Yan Zhang ◽  
Chuan-Zheng Zhang ◽  
Fu-Juan Liu ◽  
Fei-Yan Wang ◽  
Ping Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
Polyvinyl Acetate ◽  
Electrospinning Process ◽  
Diameter Distribution ◽  
Electrospinning Technique ◽  
Weight Percentage ◽  
Surface Morphologies ◽  
Scanning Electron

In this paper, the surface morphologies of polyvinyl alcohol/milk nanofibers produced via electrospinning technique were investigated. The electrospinning process was performed at various processing parameters (flow rate, applied voltage) and different polyvinyl acetate to milk ratios (100/0, 90/10, 80/20, 70/30, and 60/40). The scanning electron microscopy and Image J software were used to characterize the surface morphologies, especially the diameter distribution of electro spun nanofibers. The results of scanning electron microscopy show that the diameter of polyvinyl acetate/milk nanofibers increases with the increase of the spinning speed and spinning voltage but decreases with the increase of the weight percentage of milk in the spinning solution. The potential applications of this bicomponent nanofibers are numerous and diverse. The research results in present paper can contribute to better control of the electrospinning process and thus expanding the applicabilities, such as dressings for wound healing in sports.

The Formation and Morphology of PVA Ferrogel Nanofibre by the Electrospinning Process

2010 ◽  
Vol 650 ◽  
pp. 361-366 ◽  
Author(s):  
Tao Yu Wan ◽  
Mohammad Chowdhury ◽  
George K. Stylios
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
Flow Rate ◽  
Electrospinning Process ◽  
Magnetic Sensors ◽  
Solution Flow Rate ◽  
Solution Flow ◽  
Fiber Mats ◽  
Scanning Electron

Aqueous solutions of polyvinyl alcohol (PVA) with FeCl3 were homogenously mixed and subsequently electrospun; and its characteristics were studied as a function of voltage, tip-target distance and solution flow rate. Fiber mats of (PVA)/FeCl3 composite, in the diameter of 700–1100 nm were prepared by electrospinning. Lower concentrations of solution tended to facilitate the formation of fibres with beads. With increasing concentration, the morphology was improved with smooth and uniform fibres and the increased fibre diameters in the nano range. Spinning voltage also had an important influence on the diameters of the nano fibres, while the collection distance affected fibre diameters. Nano fibres of smaller diameter were formed when lower voltages are applied. The morphology of the electrospun from PVA/FeCl3 nano fibres and their magnetic power was observed and analyzed by scanning electron microscopy (SEM).The fibres produced in this way could potentially be applied to manufacture magnetic sensors, flexible magnets.

scholarly journals Application of rast electronic microscopy in cytohistological studies of flax

2019 ◽  
pp. 12-17
Author(s):  
I.V. Vereshchahin ◽  
N.M. Kandyba ◽  
L.M. Kryvosheeva
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Economic Value ◽  
Weather Conditions ◽  
Histological Structure ◽  
Average Cell ◽  
Resistant Varieties ◽  
Adverse Weather ◽  
Bad Weather ◽  
Scanning Electron

The article highlights the problem of lodging of flax due to adverse weather conditions. The features of the growing zone, the economic value of flax and its products are updated, as well as the damage caused by bad weather during the growing season. Flax resistance to lodging is directly related to the anatomical structure of the stem, but the authors specify that this feature is related to the structure of the submucosa (hypocotyl). The theoretical part of the article describes the flax fiber and its technological properties. Therefore, the purpose of the article was to investigate the cytisthistological structure of the transverse section of the subunit knee of stems of flax-gland by scanning electron microscopy to determine the resistance to lodging. As the object of research used varieties of Ukrainian and foreign selection: Gladiator, Merylin, Zhuravka, Kievsky 2. The weather conditions during the years of research (2016‒2018) are quite characteristic of the area of the northeast Polesie and reflect the instability of hydrothermal modes of vegetation of flax-liqueur in this zone. Testing the experimental material of these studies over three years with contrasting weather conditions allowed us to objectively evaluate the responses of flax varieties to these conditions. To perform the tasks assigned to the job laid a nursery of a comparative test. The predecessor of flax was winter wheat after many years of herbs. The main tillage was carried out according to the type of half-soil; stubble peeling, plowing to a depth of 22‒25 cm, and two cultivations as weeds germinated to a depth of 8‒10 and 5‒6 cm. Slice studies were performed using a scanning electron microscope. The article presents the results of studies of the cytologic and histological structure of stems of varieties of flax-shoots of various degrees of resistance to lodging using the method of scanning electron microscopy, presents the structure and features of sections of hypocotyl stems of plants of flax – duckweed and also the average thickness. The authors carried out 250 measurements of the thickness of the cell walls of the sections of the submucosa. It was found that in flax varieties, more resistant to lodging, cells of conductive and mechanical tissues are not deformed, unlike unstable varieties. In addition, the average cell wall thickness of resistant varieties is greater than unstable ones.

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